Record rainfall battered Japan's Chiba prefecture on Thursday, killing at least eight people, flooding homes and roads, and stranding thousands of travellers at one of Asia's busiest international airports. More than 367 millimetres of rain — the highest 24-hour total recorded in the area since comparable records began in October 2013, when 309 mm fell — inundated the low-lying region east of Tokyo during one of Japan's busiest holiday periods.

Chiba prefecture, a densely populated area that borders Tokyo to the east and is home to Narita International Airport, bore the brunt of the storm. Floodwater submerged roads and paralysed rail networks, while a power substation was flooded, cutting electricity to more than 20,000 homes. Gas supplies to nearly 13,000 households were also temporarily severed. The dead included a man in his 60s or 70s found in floodwater and a 66-year-old woman who became trapped in her submerged car. Soldiers were deployed to assist with rescue efforts as authorities issued the region's highest-level rain warning — a designation used for only the most extreme events — before downgrading it to level four by Friday morning.

At Narita Airport, around 7,000 travellers were stranded overnight after train services were cancelled. Airport staff distributed sleeping bags, water and snacks to passengers who bedded down on terminal floors. "I queued for a taxi, but the wait was four hours," said Minoru Yamasaki, a 48-year-old Chiba resident returning from holiday, who had been turned away from a hotel and returned to the airport with nowhere else to go. Some major highways were shut, clogging alternative routes across the prefecture, while hundreds of city residents spent the night in government buildings converted into evacuation centres.

"This was an extremely unusual situation," Chiba Governor Toshihito Kumagai told reporters. "I have responded to many disasters in the past, but I have never experienced a case like this." The Japan Meteorological Agency described the rainfall as unprecedented, and warned that risks of further flooding and landslides remained even after the highest alert was downgraded.

The disaster underscores Japan's acute vulnerability to extreme weather events. The country sits at the intersection of several climatic systems and experiences intense seasonal rainfall, but meteorologists noted that Thursday's deluge surpassed historical benchmarks, raising fresh questions about the growing intensity of storms in the region. Some rail services between Narita and Tokyo resumed on Friday, gradually easing congestion at the airport, where most flights were expected to return to normal operations.